Process for undulating artificial fibers



Patented June 10, 1941 PROCESS FOR UNDULATING ARTIFICIAL FIBERS Hein Israel Waterman and Willem Leendert Johannes de Nie, Delft, Netherlands, assignors to Shell Development Compan San Francisco, Calif" a corporation of Delaware No Drawing. Application April 3, 1939, Serial No. 265,744. In the Netherlands April 7, 1938 7 Claims. (Cl. 8-113) The present invention relates to an improvement in the art of fabricating artificial filaments, fibers, threads, and the like, suitable for use in theproduction of textiles and related materials. More particularly, the invention relates to a process whereby artificial fibers composed predominantly of high molecular weight polymers of vinyl compounds may be made to assume an undulated or wavy nature.

Synthetic fibers, suchas viscose silk. acetate silk, fibers produced from casein, hydrocarbon polymers, various resinous materials, and the like, are, in general, formed by spinning through a fine orifice or spinning nozzle and consequently, unless altered by special treatment, are naturally smooth and straight. Most natural fibers, on the other hand, are more or less rough, irregular and curly. As a result of their smooth, wiry nature, synthetic fibers, unless given a special treatment, are more diflicult to handle in the various textile-making processes, such as spinning and weaving, and usually-require somewhat modified technique. The textile materials made from smooth and wire-like synthetic fibers are, in general, poor heat insulators, cold to the touch, slippery, relatively unstretchable, and have an excessive luster or shine.

In order to overcome these disadvantages of the synthetic fibers, various methods, such as, for instance, spinning the filament from a vibrating spinning nozzle, etc., have been proposed to impart to the fibers the physical characteristics of special natural fibers. Synthetic filaments composed of polymers of butadiene and similar diolefinic hydrocarbons may be crimped, for example, by subjecting them to the action of organic solvents which exert a swelling action upon the fiber. According to this process, more fully described in British'Patent No. 346,799, the fiber, after being subjected to the organic swellimparted to said artificial fibers and to provide a method whereby said artificial fibers may be undulated in a more practical and economical manner.

We have found that synthetic fibers composed predominantly of high molecular weight polymers of vinyl compounds, such as, in particular,

- butadiene, may be much more rapidly and conveniently undulated by treating them with certain sulfur halides, such as, in particular, sulfur monochloride. .The process of the present invention, stated in very general terms, consists essentially in immersing the formed filament in a treating bath containing a suitable concen tration of the liquid sulfur halide and removing the undulated filament after a very short, prea of the synthetic fibers for which the present process is especially effective may be mentioned.

- fibers produced from polymerization products of ing agent for several hours at room temperature I ticular objects are to provide a method whereby undulations of the desired wave length may be butadiene, isoprene, phenyl butadiene, chloroprene, cyclopentadiene and the related diolefinic compounds which are capable of being polymerized to tough or hard materials. The fibers may, furthermore, be composed of high molecular weight materials obtained by copolymerizing or interpolymerizing a mixture of one or more polymerizable materials of the above class, and may also contain varying minor amounts of other materials intended to impart certain characteristics to the products, such as, for example, compatible resins, plasticizers, waxes, dyes, or minor amounts of other products incorporated into the filaments during the wet or dry spinning process.

The synthetic fiber, treated according to the present process, may be produced by spinning a solution of the polymer into a heated atmosphere, 1. e. by a dry spinning process, or by spinning a solution or emulsion of the polymer into a coagulatio'n or precipitation bath. In such cases where the freshly formed filament requires a subsequent hardening treatment, the treatment to produce the undulation of the fiber may be effected either prior or subsequent to such hardening treatment. When dealing with such fibers (1. e. those which require a hardening treatment) the undulation is, however, most advantageously effected prior to the hardening, since this allows the total process for producing the fibers to be materially simplified by eliminating a drying treatment.

The undulation of the fibers, according to the present invention, is effected by subjecting the fiber to the action of a halide of sulfur having the composition SXn, wherein X represents a halogen, preferably chlorine, and n is a quantity greater than about 0.60 and less than 4.00, preferably between 1.0 and 3.0. The sulfur halide may be applied in the form of solutions in inert solvents, such as carbon disulfide, liquid sulfur dioxide, etc., containing as low as by volume of the sulfur halide, but are preferably applied in considerably higher concentrations, such as concentrations ranging from 50 to 100%.

Synthetic fibers of the class in question, we have found, when subjected to the action of the above sulfur halides, assume almost immediately a fine, undulated structure. Thus, for example, an immersion period of about 2 to seconds at room temperature in the sulfur halide generally suffices to produce the desired effect. In certain cases, when dealing with unusually resistant fibers of high denier number, immersion periods as long as about two minutes may be desirable. The period of immersion most advantageously employed varies somewhat depending upon the composition, denier number and character of the particular fiber, and is preferably maintained as short as possible, i. e. immersion periods longer than necessary to produce the desired undulation are preferably avoided. The rapidity of the undulating action, and hence the most advantageous immersion period, also depends somewhat upon the concentration and temperature of the sulfur halide. In general, although temperatures ranging from near the boiling point of the sulfur halide-containing liquid down to near the freezing point of said liquid may be employed, very excellent results may usually be most conveniently obtained at temperatures of from about 0 C. to about 30 C. Higher temperatures tend to hasten the undulating action. Fibers composed of vulcanizable polymers and treated according to the present process, unlike vulcanized fibers, may, moreover, be heat hardened in the customary manner, and such treatment does not destroy their undulatory nature.

Since the undulation of the synthetic fibers may be effected by simply immersing the fiber in a bath of the sulfur halide, and since, furthermore, the process requires only a few seconds, it is exceptionally advantageous and well adapted to be executed continuously. The process may, in fact, be very advantageously effected in conjunction with the spinning steps, by simply passing the fiber, or bundle of fibers, issuing from the spinning operation through a bath containing the sulfur halide.

In such cases where the artificial filament is produced by wet spinning into a coagulation bath, the freshly coagulated filament issuing from the bath may contain appreciable quantities of alcohol, water, or other material from the coagulation bath which react with the sulfur halide. An advantage of the present process is that such fibers may be directly treated without aaeaeio first; drying to remove the last traces of coagulant. In such cases, a small amount of loose elemental sulfur is deposited upon the surface of the fiber during the treatment with the sulfur halide. This deposited sulfur, We have found, does no harm, and, in fact, is somewhat advantageous since it materially reduces the tackiness when this is prone to be present. After being subjected to the action of the sulfur halide for the desired length of time, the undulated fiber may be Washed free of any adhering elemental sulfur with a dilute solution of sodium sulfide.

A special advantage of the present process is that it allows the wave length of the undulations to be controlled. This may be very simply accomplished in the present process by controlling the tension of the filament during the treatment with the sulfur halide. Thus, if the filament, while being acted upon by the sulfur halide, is under no tension, it is found that the undulations produced are of very short wave length. If

a slight tension is applied, the wave length of the undulations increases somewhat. Upon increasing the tension, the wave length continues to increase, and finally the undulations disappear.

Synthetic filaments are customarily spun under considerable tension in order to orient the molecules in the fibers. Since, as explained above, tension tends to increase the wave length of the undulations, it will be apparent that the tension applied in the spinning process to produce stretching should be applied before the filament is subjected to the action of the sulfur halide.

After being subjected to the action of the sulfur halide to produce the desired undulations, the filament, or bundle of filaments, may be washed in warm water, a dilute solution of ammonium hydroxide, or any other suitable liquid, to remove any adhering sulfur halide. In many cases, however, such as, in particular, when the ratio of sulfur to halogen in the sulfur halide employed is low, the greater part, if not all, of any adhering sulfur halide is quickly evaporated upon withdrawing the filament from the liquid.

We claim as our invention:

1. A process for producing undulated synthetic filaments which comprises immersing a formed filament, consisting essentially of high molecular weight polymers of a vinyl compound, in a liquid, containing at least 10% by volume of a sulfur halide having a composition SXn wherein X represents a halogen and n is a quantity greater than about 0.6 and less than 4.0, for a length of time permitting undulation of said filament to occur, but for less than two minutes so that no appreciable vulcanization of said filament occurs, while maintaining insufiicient tension upon said filament to substantially remove the formed undulations by stretching.

2. A process for producing undulated synthetic filaments which comprises immersing a formed filament, consisting essentially of high molecular weight polymers of a diene hydrocarbon, in a liquid containing at least 10% by volume of a sulfur halide having a composition SXn wherein X represents a halogen and n is a quantity greater than about 0.6 and less than 4.0, for a length of time permitting undulation of said filament to be effected, but for less than two minutes so that no appreciable vulcanization of said filament occurs, while maintaining said filament sufi'iciently relaxed of tension to avoid substantially removing the undulations by stretching.

3. A process for producing undulated synthetic filaments which comprises immersing a formed filament, consisting essentially of high molecular weight polymers of a vinyl compound, in a liquid, containing at least 50% by .volume of a sulfur halide having a composition SK; wherein X represents a halogen and n is a quantity greater than about 0.6 and less than 4.0, for a length of time of at least two seconds but less than two minutes so that no appreciable vulcanization of said filament occurs, while maintaining said filament sufficiently relaxed of tension to avoid substantially removing the formed undulations by stretching.

4. A process for producing undulated synthetic filaments which comprises the steps of immersing a formed filament, consisting essentially of high molecular weight polymers of a vinyl compound, in a liquid, containing at least by volume of a sulfur halide having a composition SX wherein X represents a halogen and n is a quantity greater than about 0.6 and less than 4.0, for a length of time of at least two seconds, but for less than two minutes, whereby undulation, but substantially no vulcanization of the filament is eflected, and controlling the wave length of the undulations by controlling the tension of said filament during the immersion.

5. A process for producing undulated synthetic filaments which comprises immersing a formed filament, consisting essentially of high molecular weight polymers of a diene hydrocarbon, in a liquid, containing at least50% by volume of a sulfur halide having a composition SX; wherein X represents a halogen and n is a quantity greater than about 0.6 and less than 4.0, for a. length of time permitting undulation of said filament to occur, but for less than thirty seconds so substantially no vulcanization of said filament occurs, while maintaining insuflicient tension upon said filament to substantially remove the formed undulations by stretching.

6. A process for producing undulated synthetic filaments which comprises immersing a formed filament, consisting essentially of high molecular weight polymers of a halogen substituted derivative of a. diene hydrocarbon, in a liquid, containing at least 10% by volume of a sulfur halide having a composition SK wherein X represents a halogen and n is a quantity greater than about 0.6 and less than 4.0, for a length of time permitting undulation of said filament to be efiected, but for less than two minutes so substantially no vulcanization of said filament occurs, while maintaining said filament sufficiently relaxed of tension to avoid substantially removing the formed undulations by stretching.

'7. A process for producing undulated synthetic filaments which comprises immersing a formed filament, consisting essentially of high molecular weight polymers of a halogen substituted derivative of a diene hydrocarbon, in a liquid, containing at least by volume of a sulfur halide having a composition SXn wherein X represents a halogen and n is a quantity greater than about 0.6 and less than 4.0, for a length of time of at least two seconds, but less than two minutes so substantially no vulcanization of said filament occurs, while maintaining insumcient tension upon said filament to substantially remove the formed undulations by stretching.

I-IEIN ISRAEL WATERMAN. WIILEM LEENDERT JOHANNES DE NIE. 

